Cutting apparatus for large plates

ABSTRACT

The longitudinal ends or edges of a large plate composed of a plurality of unit plates welded together are not uniform or even and therefore the large plate cannot readily be utilized in that condition. In other words, the uneven portions on both ends of such a large plate must be cut to produce parallel ends. A cutting apparatus for large plates is provided, which mainly comprises a pair of rails disposed along the ends of a large plate and extending in the longitudinal direction thereof, a pair of cutting machines mounted on the rails to travel thereon, and a deviation detector for detecting the amount of deviation of position of a stopped large plate, whereby in accordance with the value of a detected deviation, the two rails are rotated in a parallel relation over the surface of the large plate to determine the cutting lines along the ends of the large plate, and the cutting devices are then brought into operation to remove the desired amount from both ends of the plate to produce the parallel ends.

United States Patent [1 Sekine et al.

[ June 11, 1974 CUTTING APPARATUS FOR LARGE of Yokohama; Yasuhiko Oniki, Tokyo, all of Japan [73] Assignee: Nippon Kokan Kabushiki Kaisha,

Tokyo, Japan [22] Filed: Dec. 26, 1972 21 Appl. No.: 318,490

30 Foreign Application Priority om Feb. 8, 1972 Japan 47-013271 [56] References Cited UNITED STATES PATENTS 5/1940 Trosch 90/15 X 11/1968 Torwegge 83/368 PARALLEL- DETECTOR Primary Examiner-Roy Lake Assistant ExaminerPaul A. Bell Attorney, Agent, or Firm-Flynn & Frishauf [57] ABSTRACT The longitudinal ends or edges of a large plate composed of a plurality of unit plates welded together are not uniform or even and therefore the large plate cannot readily be utilized in that condition. In other words, the uneven portions on both ends of such a large plate must be cut to produce parallel ends. A cutting apparatus for large plates is provided, which mainly comprises a pair of rails disposed along the ends of a large plate and extending in the longitudinal direction thereof, a pair of cutting machines mounted on the rails to travel thereon, and a deviation detector for detecting the amount of deviation of position of a stopped large plate, whereby in accordance with the value of a detected deviation, the two rails are rotated in a parallel relation over the surface of the large plate to determine the cutting lines along the ends of the large plate, and the cutting devices are then brought into operation to remove the desired amount from both ends of the plate to produce the parallel ends.

14 Claims, 8 Drawing Figures PARALLEL- DETECTOR a. 1: AMP

SHEET 10F 4 PATENT {mum 1 m4 Timunn 814 PAT SHEET20F 4- FIG.3

CUTTING APPARATUS FOR LARGE PLATES BACKGROUND OF THE INVENTION The present invention generally relates to cutting apparatus for large plates and more particularly to a cutting apparatus which is designed to cut large plates such as skin or shell plates used as hull blocks with a higher efficiency and great accuracy.

It has been customary in the art to parallel-cut unit plates in the longitudinal direction with a flame planer (parallel cutting machine) and then to weld a plurality of the parallel-cut unit plates together by means of oneside welding, thereby producing a large plate of any desired size for use as a hull block, for example. The end faces of the large plate thus produced are not straight or parallel (see FIG. 8 of the accompanying drawings) and hence it has been the practice to manually cut the uneven portions on both end faces of the plate to trim the end faces. In FIG. 8, the broken lines indicate the lines of cutting. However, there is a disadvantage in that since the cutting operation is effected manually with the resultant extreme inefficiency and lack of satisfactory parallelism between the lines of cut, the working efficiency is adversely affected when the aligning operation of the blocks is performed on a building slip.

It is therefore an object of the present invention to solve these difficulties.

It is another object of the present invention to provide a cutting apparatus for large plates comprising a pair of rails respectively disposed on each side of a conveyance device such as a roller conveyor for transporting large plates, that is, in the vicinity of each end of a large plate and rotatable in a plane, a deviation detector for detecting deviation of position of a large. plate and a stopper arranged between the ends of the rails (stopper line), a rotation detector provided for each of the rails, and a cutting device mounted on each of the rails to travel therealong.

SUMMARY OF THE INVENTION The present invention is directed primarily to a cutting apparatus for large plates comprising a conveyance device for transporting a large plate, a rotatable longitudinal rail disposed on each side of said conveyance device and movable in accordance with the width of said large plate so as to be positioned substantially perpendicular to seams in said large plate, a cutting device operated by a motor to travel along each of said longitudinal rails, a detector including a differential transformer for each of said longitudinal rails to detect the degree of rotation thereof, and a deviation detector including differential transformers for detecting the deviation of the stopping position of said large plate, said deviation detector being located near a stopper line, at which line said large plate is stopped in transit, whereby when the large plate transported by the conveyance device is brought to a stop near the stopper line. The deviation detector detects the deviation of the stopping position of the large plate from a desired position. More particularly. it detects the deviation between the center line of the conveyance device and the center line of the large plate stopped on the conveyance device. so that at least one of the longitudinal rails on both sides of the large plate is moved in accordance with the detected deviation with respect to the width of the large plate and at the same time both of the longitudinal rails are located to adjust the positions thereof so as to reposition the rails substantially perpendicular to the seams in the large plate and thereafter to cause the cutting device on each of the longitudinal rails to travel therealong to cut the ends of the large plate.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a diagrammatic plan view showing the general construction of a large plate cutting apparatus according to the present invention;

FIG. 2 a front elevation of FIG. 1;

FIG. 3 is a sectional view taken along the line III-Ill of FIG. 1, showing in detail the pivot portion at the center of the fixed rail;

FIG. 4 is a sectional view taken along the line IVIV of FIG. 1, showing in detail the pivot portion at each end of the fixed rail;

FIG. 5 is an enlarged view of the section A in FIG. 2, showing in detail the supporting structure of the cutting device;

FIG. 6 is a sectional view taken along the line VIVI of FIG. 1, showing in detail the pivot portion at each end of the movable rail;

FIG. 7 is a sectional view taken along the line VII- VII of FIG. 1, showing in detail the pivot portion at each end of the movable rail; and

FIG. 8 is a perspective view of a large plate which may be subjected to the cutting operation by the apparatus of the present invention.

DETAILED DESCRIPTION OF THE INVENTION A large plate 1 which may be subjected to a cutting operation by the apparatus of the present invention is composed of a plurality of unit plates 2 cut out and welded preliminarily by separate processes and apparatus. In such a large plate, as shown in FIG. 8, its longitudinal ends 3 and 4 tend to become uneven and therefore it is necessary to trim the ends 3 and 4 to produce the parallel ends 3 and 4 along the lines X and Y as the cutting lines. For this purpose, the large plate 1 is moved over conveyance means 5 and 6, such as, rollers from the direction of the broken line arrow in FIG. 1 and it is fed into a large plate cutting apparatus according to the present invention. In this case, the center line of the large plate 1 thus fed to the apparatus does not necessarily coincide with the center line of the conveyance device. Accordingly, the placement of the large plate is confirmed by a deviation detector that will be explained later, so that longitudinal rails are rotated according to the detected deviation. In the discussion to follow, the term large plate means a large steel plate, but the present invention is not intended to be limited to the steel plate and any material which must be cut to produce parallel ends may be subjected to the cutting operation by the apparatus according to the present invention. The terms longitudinal and transverse are also used to indicate respectively the longitudinal direction and the transverse direction in FIG. 7.

The large plate 1 fed into the large plate cutting apparatus is positioned by means of a stopper (not shown) of a known type which is arranged at a stopper line 7. Disposed on one side of the conveyance means 6 are transverse rails 8, 9 and 10 which are arranged substantially perpendicular to the conveyance means 6, and tables l1, l2 and 13 movable from side to side are 3 provided respectively on the transverse rails. A longitudinal rail on which a cutting device 14 travels, is mounted on the tables 11, 12 and 13. Motors 16 and- 17 are respectively provided for the tables 11 and 13 so that the operation of these motors moves the longitudinal rail 15 to the left or right in the illustration on the transverse rails 8, 9 and 10. To move the longitudinal rail 15 to the left or right in accordance with the width of the large plate 1 brought into the apparatus by the conveyance means 6, it is necessary that the motors l6 and 17 are operated by a single actuating switch which is controlled from acontrol panel (not shown) so as to move the longitudinal rail 15 entirely parallel to the large plate 1.

On the other hand, the table 12 is providedwith a shaft (which will be explained later) for rotating the longitudinal rail 15in the plane, so that when either the motor 16 or 17 is operated to move the table 11 or 13 in the transverse direction, the longitudinal rail 15 is rotated clockwise or counterclockwise in the plane with its intermediate point 18 as a supporting point. The position. of the longitudinal rail 15 and that of another longitudinal rail 35 which will be explained later, have been designed and set according to the center line of the cutting apparatus in the course of the designing of the latter and therefore it is necessary to adjust the positions of the longitudinal rails 15 and 35 to conform with a large plate'fed to the cutting apparatus with a certain deviation to the center line thereof. In other words, the rotational movement of the longitudinal rails is effected in accordance with the degree of deviation of the arrived large plate 1 with respect to the center line of the conveyance device, thereby adjusting the positions of the longitudinal rails to be placed substantially perpendicular to the seams in the large plate 1 (shown at 19, 20 and 21 in FIG. 8). In this case, the transition from the lateral to rotational movement of the longitudinal rail 15 is effected from the control panel (not shown).

The longitudinal rail 35 is arranged on the other side (the left side in the illustration) of the conveyance device so that similarly with the longitudinal rail 15, a cutting device 34 can travel along the longitudinal rail 35. The longitudinal rail 35 is mounted on tables 31 and 33 which are adapted to move to the left and right on transverse rails 38 and 39, so that when the motors 36 and 37 are operated to move the tables 31 and 33 in the like manner as the longitudinal rail 15, the longitudinal rail 35 is rotated in either the clockwise direction or counterclockwise direction, depending upon the direction of rotation of the motors with the intermediate point 32 acting as its supporting and pivot point. However, it is to be noted that the longitudinal rail 35 is not adapted to move entirely to the left or right in accordance with the width of the large plate 1.

As the large plate 1 is conveyed and placed between the longitudinal rails 15 and 35, its further movement in the direction of the broken arrow is stopped by the previously mentioned stopper (not shown) disposed on the stopper line 7, thereby bringing the large plate 1 to a standstill. Preliminarily disposed near this position is a plate-position deviation detector 22 comprising differential transformers 23 and 24 mounted at the ends thereof, whereby when the upper end of the large plate 1 comes into contact with the differential transformers 23 and 24, the degree of deviation of the plate 1 is detected and translated into an electrical potential. The

plate-position deviation detector 22 can also serve as a stopper and thus it is possible to eliminate the previously mentioned stopper.

Detectors 25 and 26 are respectively provided for the longitudinal rails 15 and 35 at near the center thereof to detect the degrees of rail rotation. The rail rotation detectors 25 and 26 are respectively provided withdifferential transformers 27 and 28 which respectively convert the degrees of rotation of the longitudinal rails 15 and 35 into electrical potentials. Thus, either the motors l6 and 36 or the motors 1'7 and 37 are operated in accordance with the differences between the potentials produced by the differential transformers 23 and 24 and those produced by the differential transformers 27 and 28, thereby rotating the longitudinal rails 15 and 35 clockwise or counterclockwise until the deviations of lines X and Y for cutting the large plate 1 from the lines in which the cutting devices 14 and 34 are made to travel, are reduced to zero thus making the lines parallel to one another. The motors l6 and 36 or 17 and 37 stop rotating when the potential differences become zero.

The present invention will be explained in more detail with reference to FIGS. 3 and 4. FIG. 3 illustrates in detail a'section taken through the middle portion of the longitudinal rail 35. A rotary shaft 41 secured to the lower end of the longitudinal rail 35 and extending downwardly therefrom is fit in a frame 40 firmly set on the ground. The rotary shaft 41 is provided with a plurality of bearings 42, 43, 44 and45 which are mounted respectively at the peripheral and end portions thereof to facilitate the rotation of the shaft 41 in the frame 40. The middle portion of another longitudinal rail 15 is constructed substantially in the same manner as shown in FIG. 3 and therefore no detailed explanation thereof will-be made. FIG. 4 is a detailed view of the pivotted end portion of the longitudinal rail 35 (i.e., the portion at which the longitudinal rail 35' is connected to the table 31 or 33) in which a shaft 47 integrally formed with the transverse rails 38 and 39 is placed rotatably in a frame 46 which is firmly set on the ground. When the longitudinal rail 35 is rotated clockwise or counterclockwise with the middle point 32 as its supporting point, the transverse rails 38 and 39 also rotate with the shaft 47 as the supporting point thereof in accordance with the degree of rotation of the longitudinal rail 35. Similarly with the construction shown in FIG. 3, bearings 48 and 49 are mounted respectively on the sides and the end of the shaft 47 to facilitate its rotation. The transverse rail 38 or 39 integral with the shaft 47 is formed on the upper surface thereof with a V-shaped groove 50 extending in the longitudinal direction inthe illustration and a V-shaped projection on the lower surface of the table 31 or 33 supporting the longitudinal rail 35 is fit in the groove 50. Thus, in response to the operation of the motor 36 or 37, the table 31 or 33 is moved, with the V-shaped groove 50 acting as a guide therefor, in the longitudinal direction in the illustration (to the left or right in FIG. 1 Numerals 52 and 53 designate bearings.

Referring now to FIG. 5, there is illustrated in detail the supporting structure for the cutting device. The supporting structures for the cutting devices 14 and 34 are identical in construction and therefor only the supporting structure for the cutting device 14 will be explained with reference to FIG. 5. The cutting device 14 comprises a vertically movable rod 55 having torches 54 mounted thereon and the cutting device 14 is carried on an arm 56. Numeral 57 designates a motor for moving the cutting device 14 and the motor 57 is securely mounted on a frame 58 of the arm 56. The motor 57 rotates a pinion 60 which is in mesh with a rack 59. The rack 59 extends along the longitudinal length of the longitudinal rail on the upper surface thereof and thus the cutting device 14 can travel along the longitudinal rail 15. The frame 58 is provided with rollers 61, 62 and 63, 64 respectively holding therebetween the ends of the longitudinal rail 15 from the upper and lower sides thereof and in this way the cutting device 14 can travel along the rail 15 smoothly without rattling.

FIGS. 6 and 7 show the lower structure of the longitudinal rail 15, particularly those portions of the longitudinal rail 15 which are connected to the transverse rails 8 and 10. The structures in these portions are identical and therefore the description will be limited to the structure of the connection between the transverse rail 8 and the longitudinal rail 15.

In the Figures, numeral 65 designates a bed firmly set on the ground and the transverse rail 8 is securely mounted on the bed 65. The transverse rail 8 has a rack 66 securely mounted thereon and the rack 66 is in mesh with a pinion 67 of the motor 16 mounted on the table 11, so that the table 11 is moved to the left or right in FIG. 6 in response to the operation of the motor 16. Rollers 68, 69, 70, 71, 72 and 73 are provided so that the table 11 may be moved smoothly, and these rollers also hold therebetween the ends of the transverse rail 8 from the upper and lower sides as well on both sides thereof. Mounted on the table 11 is a support 74 secured to the lower end of the longitudinal rail 15. The support 74 is formed with a groove 75 having r a rectangular cross section as shown in FIG. 6 and a roller 76 mounted on the upper surface of the table 11 is placed in the groove 75, whereby the table 11 is moved in the direction of the arrow in FIG. 7 when the longitudinal rail 15 rotates. Numeral 77 designates bearings which serve to reduce the friction which occurs between the support 74 and the table 11 during the rotational movement of the longitudinal rail 15.

With the construction described above, the operation of the cutting apparatus according to the present invention will now be explained.

When the large plate 1 carried on the conveyance device (e.g., a disk roller conveyor) arranged between the longitudinal rails 15 and 35 is fed into the cutting apparatus, further movement of the large plate 1 is stopped by the stopper (not shown) preliminarily arranged along the stopper line 7. Concurrently with the stoppage of the plate, the deviation of position of the large plate 1 (the deviation of the center line of the stopped large plate from the center line of the conveyance device) is detected by means of the differential transformers 23 and 24 of the deviation detector 22 contacted with the large plate 1 and the differential transformers 27 and 28 of the rail rotation detectors 25 and 26. As a result, the positions of the longitudinal rails 15 and 35 are adjusted in such a manner that they are arranged perpendicular to the seams 19, and 21 in the large plate 1.

Thereafter, the cutting devices 14 and 35 travel respectively along the longitudinal rails 15 and 35, so that the torches of these cutting devices remove, with mechanical accuracy and great efficiency, the desired amount from the longitudinal ends of the large plate 1 to produce parallel ends. In this case, however, the cutting devices 14 and 34 need not necessarily be operated in synchronism with each other.

It will thus be seen from the foregoing description that the cutting apparatus for large plates according to the present invention is designed such that the deviation with respect to the center line of the conveyance means of a large plate fed to the cutting apparatus is detected and the rails having the cutting devices mounted thereon are rotated in accordance with the detected deviation to adjust the positions of the rails to meet the detected deviation and thus to remove the desired amount from both ends of the large plate by the cutting devices to produce parallel ends. Thus, there is an ad vantage in that large plates with highly improved parallel ends and improved quality can be produced and moreover, automatic operation is possible with the resultant improvement in working efficiency.

We claim:

1. A cutting apparatus for cutting the ends of a large plate to produce parallel ends, said cutting apparatus comprising:

conveyance means for transporting a large plate,

a rotatable longitudinal rail disposed on each side of said conveyance means, at least one of said longitudinal rails being movable in accordance with the width of said large plate so as to be positioned sub stantially perpendicular to seams in said large plate,

a cutting means for travelling along each of said longitudinal rails,

a detector for detecting the degree of rotation of each of said longitudinal rails and having a differential transformer, and

a deviation detector having a plurality of differential transformers and located near a stopper line, at which line said large plate is stopped in conveyance, to detect a deviation of position of said large plate.

2. An apparatus according to claim 1, wherein at least one of said longitudinal rails is mounted on a plurality of tables movable respectively along a plurality of transverse rails arranged substantially perpendicular to the lines on which said plate is cut, and a shaft mounted on the lower face of the central portion of said at least one longitudinal rail is rotatably received in one of said plurality of movable tables.

3. An apparatus according to claim 1, wherein at least one of said longitudinal rails has a shaft mounted on the lower face of the central portion thereof and rotatably received in a fixed frame, each end of said at least one rail is supported on a table movably mounted on a transverse rail, and each of said transverse rails includes a shaft rotatably received in a fixed frame.

4. An apparatus according to claim 3, wherein said transverse rail with the shaft extending from the lower face thereof is formed with a V-shape groove on the upper surface thereof, and said table mounted on said transverse rail is provided with a V-shaped projection on the lower face thereof, whereby said table is movable through the intermediary of bearings on said transverse rail with said V-shaped groove acting as a guide therefor.

5. An apparatus according to claim 1, wherein each of said cutting means is mounted through the intermediary of an arm on a frame having mounted thereon a plurality of rollers holding therebetween the ends of the longitudinal rail from upper and lower sides thereof, a pinion meshed with a rack disposed on the upper surface of said longitudinal rail to extend along the longitudinal length thereof, and a motor for rotating said pinion.

6. An apparatus according to claim 1, wherein the detected values of said deviation detector for contacting and detecting the deviation of position of the large plate and said rotation detectors are converted into electrical values, whereby said longitudinal rails are rotated until the difference between said electrical values is reduced to zero.

7. An apparatus according to claim 1 wherein at least one of said longitudinal rails is movable in the direction of the width of said large plate, and both of said longitudinal rails are rotatable so as to be positionable substantially perpendicular to the seams in said large plate.

8. An apparatus according to claim 1 wherein said conveyance means comprises a roller conveyor.

9. An apparatus according to claim 1 comprising means for stopping the conveyance of said large plate substantially at said stopper line.

10. An apparatus according to claim 9 wherein said deviation detector includes said stopping means.

11. An apparatus according to claim 1 comprising a motor coupling said cutting means to said respective longitudinal rails for causing said respective cutting means to travel along each of said longitudinal rails.

12. An apparatus according to claim 3 wherein said transverse rails have their shafts integrally formed with said rails.

13. An apparatus according to claim 1 wherein said deviation detector detects the deviation of the edge of the large plate which is stopped at or near said stopper line from a predetermined position.

14. An apparatus according to claim 1 wherein said longitudinal rails are rotatable in a plane which is parallel to the plane in which the flat surface of said large plate lies. 

1. A cutting apparatus for cuTting the ends of a large plate to produce parallel ends, said cutting apparatus comprising: conveyance means for transporting a large plate, a rotatable longitudinal rail disposed on each side of said conveyance means, at least one of said longitudinal rails being movable in accordance with the width of said large plate so as to be positioned substantially perpendicular to seams in said large plate, a cutting means for travelling along each of said longitudinal rails, a detector for detecting the degree of rotation of each of said longitudinal rails and having a differential transformer, and a deviation detector having a plurality of differential transformers and located near a stopper line, at which line said large plate is stopped in conveyance, to detect a deviation of position of said large plate.
 2. An apparatus according to claim 1, wherein at least one of said longitudinal rails is mounted on a plurality of tables movable respectively along a plurality of transverse rails arranged substantially perpendicular to the lines on which said plate is cut, and a shaft mounted on the lower face of the central portion of said at least one longitudinal rail is rotatably received in one of said plurality of movable tables.
 3. An apparatus according to claim 1, wherein at least one of said longitudinal rails has a shaft mounted on the lower face of the central portion thereof and rotatably received in a fixed frame, each end of said at least one rail is supported on a table movably mounted on a transverse rail, and each of said transverse rails includes a shaft rotatably received in a fixed frame.
 4. An apparatus according to claim 3, wherein said transverse rail with the shaft extending from the lower face thereof is formed with a V-shape groove on the upper surface thereof, and said table mounted on said transverse rail is provided with a V-shaped projection on the lower face thereof, whereby said table is movable through the intermediary of bearings on said transverse rail with said V-shaped groove acting as a guide therefor.
 5. An apparatus according to claim 1, wherein each of said cutting means is mounted through the intermediary of an arm on a frame having mounted thereon a plurality of rollers holding therebetween the ends of the longitudinal rail from upper and lower sides thereof, a pinion meshed with a rack disposed on the upper surface of said longitudinal rail to extend along the longitudinal length thereof, and a motor for rotating said pinion.
 6. An apparatus according to claim 1, wherein the detected values of said deviation detector for contacting and detecting the deviation of position of the large plate and said rotation detectors are converted into electrical values, whereby said longitudinal rails are rotated until the difference between said electrical values is reduced to zero.
 7. An apparatus according to claim 1 wherein at least one of said longitudinal rails is movable in the direction of the width of said large plate, and both of said longitudinal rails are rotatable so as to be positionable substantially perpendicular to the seams in said large plate.
 8. An apparatus according to claim 1 wherein said conveyance means comprises a roller conveyor.
 9. An apparatus according to claim 1 comprising means for stopping the conveyance of said large plate substantially at said stopper line.
 10. An apparatus according to claim 9 wherein said deviation detector includes said stopping means.
 11. An apparatus according to claim 1 comprising a motor coupling said cutting means to said respective longitudinal rails for causing said respective cutting means to travel along each of said longitudinal rails.
 12. An apparatus according to claim 3 wherein said transverse rails have their shafts integrally formed with said rails.
 13. An apparatus according to claim 1 wherein said deviation detector detects the deviation of the edge of the large plate which is stopped at or near said stopper line from a predetermined position.
 14. An apparatus according to claim 1 wherein said longitudinal rails are rotatable in a plane which is parallel to the plane in which the flat surface of said large plate lies. 